Mobile radio antennas for mobile radio base stations are normally constructed such that two or more antenna element arrangements, which are located one above the other, are provided in the vertical direction in front of a reflector plane. These antenna element arrangements are formed, for example, from dipoles or patch antenna elements. These may be antenna element arrangements which can transmit (and can transmit and receive at the same time) only in one polarization or, for example, in two mutually perpendicular polarizations. The entire antenna arrangement may in this case be designed for transmission in one band or in two or more frequency bands by using, for example, two or more antenna elements and antenna element groups which are suitable for the various frequency bands.
Depending on the requirements, mobile radio antennas are required which have different length variants. The length variants in this case depend, inter alia, on the number of individual antenna elements or antenna element groups to be provided, in which case identical or similar antenna element arrangements are generally arranged repeatedly one above the other.
Such antennas or antenna arrays may typically have a common reflector for all the antenna element arrangements. This common reflector is normally formed by a reflector plate which may be stamped, curved and bent. Such a stamped, curved and/or bent reflector plate may, for example, make it possible to form a reflector edge area, which projects forwards from the reflector plane, on the two opposite side vertical edges. Furthermore, if required, additional sheet-metal parts may be soldered on the reflector. The use of profiles is also known. For example, extruded profiles made of aluminum etc., which are likewise fitted on or in front of the reflector plane.
In addition, costly, complex, three-dimensional functional surfaces for the antenna element arrangements are advantageous(and may even be necessary) for certain applications. In the past, a large number of connecting points and contact points have been required on the reflector in order to produce such surrounding conditions for the antenna element arrangement. Some of the parts and components which are used are in this case also still in some cases made of different materials. However, this results in a number of disadvantages. Firstly, the large number of different parts and the major assembly effort associated with them can be disadvantageous. Overall, these result in comparatively high production costs. Another disadvantage is the large number of contact points. A large number of contact points can contribute to undesirable intermodulation products. Adequate functional reliability can often be achieved only by taking the greatest possible care during assembly. On the other hand, the antennas that are produced in this way generally have a restricted function and load capability since, particularly in the case of unsuitable material combinations or even if there are only a small number of bad contact points, it may not be possible to comply with the requirements relating to the undesirable intermodulation products. If a test run of the checked polar diagram of an antenna reveals problems, then in this case it is also not immediately possible to state which contact points may have contributed to the deterioration in the intermodulation characteristics.
The illustrative non-limiting technology described herein provides an improved capability to produce antennas with high quality characteristics, and to do this to a comparatively high quality standard.
The illustrative non-limiting exemplary technology described herein provides an antenna, in particular for the mobile radio field, which takes account of very stringent quality requirements. Undesirable modulation products are avoided, or are considerably less than with conventional solutions. A considerable improvement in quality is obtained by the fact that the additional cables and electrical components which are provided for antennas, are provided separately and are generally accommodated on the rear face of the reflector device are, in an exemplary illustrative non-limiting arrangement, at least partially integrated in the reflector.
For this purpose, the exemplary illustrative non-limiting arrangement also provides for the reflector or, if the reflector is formed for example from two or more reflector modules which can be joined together, for at least one of the reflector modules to be formed integrally, at least in its basic version, namely preferably using a casting, deep-drawing, thermoforming or stamping method, or using a milling method. In some cases, a master gauge method is also spoken of in this context. The reflector module may thus be formed, for example, from a die-cast aluminum part or, in general, from a cast metal part or else from a plastic injection-molded part, which is subsequently provided with a metalized surface on one or both opposite surfaces.
The exemplary illustrative non-limiting arrangement therefore provides for a reflector module which has been produced using a casting, deep-drawing, thermoforming or stamping method, or for example alternatively using a milling method, preferably to have further integrated parts, or parts of further components, which are required in particular in conjunction with an antenna, on the rear face of the reflector, opposite the antenna element modules. This allows functional integration to be achieved in the reflector, associated with further significant advantages. The following functional elements may, for example, be integrated in the reflector module without any problems:                It is thus possible also to integrally form outer conductor contours for carrying radio-frequency signals, for example a grooved cable, coaxial cable, stripline etc., on the front face or else in particular also on the rear face of the reflector.        In the same way, contours may be integrally formed for electromagnetic screening of assemblies.        Housing parts for RF components such as filters, diplexers, distributors and phase shifters may also be integrally formed, such that all that needs to be done after incorporation of the additional functional parts in these assemblies is to fit a cover as well.        Particularly if metalized plastic parts are used as the basis for the reflector, complete cable structures can also be integrated by suitable measures such as hot stamping, two-component injection molding methods, laser processing, etching methods or the like (“three-dimensional printed circuit board”).        Interfaces for holding components for attachment or mounting as well as interfaces for accessories, for example in the form of attachment flanges, beat flanges etc., can also be provided.        
One exemplary illustrative non-limiting solution also proposes that the functional parts be provided on one or more reflector modules rather than on an integrally formed overall reflector. In other words, a reflector can be formed from at least two reflector modules, which can be joined together. To this extent, one exemplary illustrative non-limiting implementation proposes that antennas with an identical or similar function be constructed in different length variants, with comparatively little effort. In this case, the reflector devices can also be used for different antennas which, for example, can accommodate different antenna element groups or antenna element assemblies. Complex three-dimensional surrounds with functional surfaces in the transverse and/or longitudinal directions or in other directions of the reflector can be provided by simple means. Functional surfaces such as these may, for example, alternatively be provided aligned at an angle to the major axis, for example generally the vertical axis in which the reflector extends.
At the same time, the antenna or reflector configuration makes it possible to considerably reduce the number of contact points. In turn, this makes it possible to reduce the large number of different parts and the assembly effort, with a high degree of functional integration as well.
The reflector preferably has an edge. The edge may be at least on its two longitudinal faces or at least on one relatively narrow transverse face. In one exemplary illustrative implementation, the edge may preferably be on its two longitudinal faces and on its two end faces. If the reflector is formed from at least two or more reflector modules which can be joined together, then in an exemplary illustrative non-limiting implementation, at least one, or preferably all, of the reflector modules each have a corresponding edge on the two longitudinal faces and on the at least one relatively narrow transverse face. Thus, not only are side boundary webs which extend transversely with respect to the reflector plane, or boundary surfaces, provided on the two opposite vertical side surfaces, but at least on one of the end face surfaces, and preferably on both opposite end face surfaces. Each reflector or each reflector module in this case also has at least one fixed integrated central transverse web, which comprises at least one upper and one lower field for antenna element arrangements which can be used . At least two antenna element surrounds are thus, in an exemplary illustrative non-limiting implementation, defined for a reflector, or for each reflector module if the reflector is formed from at least two reflector modules. These antenna element surrounds are, in an illustrative exemplary non-limiting implementation, produced by an end-face boundary wall, two sections of the vertical side longitudinal boundaries and the at least one web wall which runs transversely with respect to the side boundary walls.
A reflector module formed in this way is also suitable for being joined to at least one further reflector module, for example of the same physical type, at the end face to form an entire reflector arrangement with a greater vertical extent.
One preferred exemplary illustrative non-limiting implementation provides for a final reflector to be formed from at least two reflector modules which are joined together with the same orientation. In an alternative exemplary illustrative non-limiting implementation refinement, it is also possible to join the end faces of two reflector modules together, with the two reflector modules being aligned with their basic shapes at 180° to one another. This assembly has been found to be particularly advantageous when the two opposite end face surfaces have different shapes, that is to say when only one end face surface is suitable for actually joining it to a next reflector module.
Reflector modules may also be joined together with different shapes but with a comparable basic structure, as described above.
As is known, the forces which act on a reflector and the operating loads which are produced by the actions of these forces, for example resulting from vibration, wind and storms, should not be underestimated. Loads such as these naturally occur particularly strongly at the junction point in an exemplary illustrative non-limiting reflector arrangement when using at least two modules whose end faces are joined together. In this case, however, moving and undefined contacts should also generally not be used in order to avoid undesirable intermodulation problems.
One exemplary illustrative non-limiting implementation therefore provides for the corresponding end walls to be appropriately matched for joining together at least two reflector modules. For this purpose, attachment points for such joined-together reflector modules may be offset with respect to one another in two planes. This makes it possible firstly to transmit and to absorb comparatively large moments, while at the same time providing functionally reliable electrical contact points. In this case, an electrically conductive contact can be made between the two reflector modules in the area of their end walls that are joined together, or else they can also be connected to one another without any electrically conductive connection(for example by inserting an insulating intermediate layer, for example a plastic layer or some other dielectric) between them. In some circumstances, a damper material can also preferably be used for the intermediate joint for an insulating layer such as this, which means that the two reflector module halves may even oscillate to a certain extent with respect to one another, to a restricted extent, even in a severe storm. This thus serves to improve mechanical reliability.
The offset plane of the attachment points, that has been mentioned, also serves to ensure that shape discrepancies are not additive at the connecting interface. If necessary, this can be compensated for with comparatively few problems, for example in such a way that production tolerances can be compensated for. If, for optimization of the polar diagram of an antenna, it is necessary or desirable to attach additional metallic elements at specific points in the reflector, then, in one development of an exemplary illustrative non-limiting implementation, these additional elements may be used, for example, in the form of electrically conductive strips, webs etc., by means of separate holding devices. The separate holding devices may be, in one illustrative exemplary non-limiting implementation, electrically nonconductive holding devices which are preferably formed from plastic or from some other dielectric, which can be fitted to the existing intermediate webs or side boundary wall sections, and between which the metallic elements which have to be inserted in addition can then be hooked in. This capacitive anchoring then once again furthermore avoids undesirable intermodulation products.